Mariner 115 1994 Can't Get To Full Speed

[KTron22]

I'm having issues with my 1994 Bayliner w/ a Mariner 115.

When I accelerate from wake speeds, it accelerates fine until half way to full throttle then it seems to get bogged down. It's not getting nearly the speed that it should, maybe 15-20 miles an hour.

There is no issue with the way it runs, it runs great, it just will not get to full speed.

I'm wondering what could be causing this loss in power.

My shop has suggested a spun prop, the enrichment valve, and possibly a need to re-build the carbs, all over the phone, but before I put it in the shop for 3 weeks, I'm looking for some advice.

 

[Chris1956]

Re: Mariner 115 1994 Drag at Full Speed

Re: Mariner 115 1994 Drag at Full Speed

It is possible that it is loading up with raw fuel. Inspect the fuel pump diaghram for holes, and rebuild the fuel pump as necessary.

if the carb makes the transition to high speed (this occurs at 2000RPM) without incident, the carbs are probably fine. Check the spark plugs color to see that it is brown.

 

[KTron22]

Re: Mariner 115 1994 Drag at Full Speed

Re: Mariner 115 1994 Drag at Full Speed

Some additional info...

The engine was rebuilt in 2007.

We had the spark plugs replaced last weekend, which helped some.

The guys at the shop said the carbs looked fine.

They said all were getting gas...

 

[KTron22]

Re: Mariner 115 1994 Can't Get To Full Speed

Bump

 

[sschefer]

Re: Mariner 115 1994 Can't Get To Full Speed

If it's a fuel problem then I would check the accelerator pump all the way to the injectors on the block. The injectors can be taken apart and cleaned and the diaphram can be replaced in the accelerator pump. Check to be sure the line from the T to the accelerator pump is clear, check that the line to the injectors is clear and that the return back to the fuel main line T is clear. Test the injectors after cleaning with a vacumm gauge to make sure the check valves are working properly.

 

[guitchess]

Re: Mariner 115 1994 Can't Get To Full Speed

I am having a similar problem and some of my research is pointing toward a problem with the switch box. You might want to research that as well.

 

[The_Kid]

Re: Mariner 115 1994 Can't Get To Full Speed

My 95 115 Mariner was doing the same thing last year. The motor only provides power with the bottom 2 cylinders until you hit about 2000 RPM when the high speed jets for the top 2 kick in. While you're running at max speed push in on the key which will dump additional fuel into the upper carbs. If you gain speed then your carbs are dirty.

It took me a while to track down my problem. I rebuilt the fuel pump and replaced both fuel filters to start with. Didn't help at all. Pulling the carbs, cleaning and rebuilding them got me back to full speed.

 

[jrpotts01]

Re: Mariner 115 1994 Can't Get To Full Speed

Hello,
Use a pair of insulated pliere and with the engine running start pull the plug wires one by one to make sure your coils are all firing. I had 2 that were not firing at idle and couldn't even feel it until I got on the water and couldn't get the boat above 6.5MPH. Turns out I had a bad Trigger. Good Luck